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ID Date Author Type Categoryup Subject
  7665   Fri Nov 2 20:41:53 2012 JenneUpdateAlignmentAS, REFL camera shots

These don't show anything too interesting, but we're including them to show where the beams are right now on the cameras, so we can compare on Monday.

 

AS:

AS_2Nov2012.png

 

REFL:

REFL_2Nov2012.png

 

 

  7666   Fri Nov 2 21:40:04 2012 ManasaUpdateAlignmentAS, REFL camera shots

 

 To get the camera shot of AS, Y1 mirror on the path was replaced by a 99% BS and transmitted beam was directed to the camera via a 50-50 BS (ND filters were distorting the image on the camera introducing fringes).

  7667   Sat Nov 3 10:31:59 2012 ranaUpdateAlignmentPOP, POX, POY, IPPOS, IPANG, REFL all coming out of vac

  That's good, but I request two things:

1) Check that the REFL beam is coming from the HR surface and not the AR surface. The real REFL beam should have as much power as the Faraday output. And where does the AR surface reflection go?

2) Use frame grabber to get as many images of the spot positions on the mirrors as is reasonable. Don't endanger bumping the tables again, but take what images can be gotten by remote camera views.

  7668   Mon Nov 5 09:53:35 2012 JenneUpdateAlignmentAS, REFL camera shots

Today's photos:

AS:

AS_5Nov2012.png

 REFL:

REFL_5Nov2012.png

IPANG / IPPOS trends:

IPPOS_IPANG_weekend_trend.png

 

 c.f. screen caps from Friday:

Quote:

These don't show anything too interesting, but we're including them to show where the beams are right now on the cameras, so we can compare on Monday.

 

AS:

AS_2Nov2012.png

 

REFL:

REFL_2Nov2012.png

 

 

 

  7671   Mon Nov 5 19:38:52 2012 jamie, jenne, ayaka, denUpdateAlignmentmore alignment woes

Earlier this morning we thought things were looking pretty good.  IPPOS, IPANG, and the AS and REFL spots looked like they hadn't moved too much over the weekend.  Our plan was to do a quick check of things, check clearances, etc., tweak up the oplevs, and then close up.  This is when I made the ill-fated decisions to check the table levelling.

The BS table was slightly off so I moved one of the thick disk weights off of the other disk weight that it was sitting on, and on to the table next to it.  This seemed to improve things enough so I left it there.  ITMY didn't need any adjustment, and I move a couple smaller weights around on ITMX.  Meanwhile Jenne was adjusting the output PSL power back into it's nominal range (<100mW), and re-tweaking up the mode cleaner.

When we then looked at the vertex situation again it was far off in yaw.  This was clearly evident on PZT2, where the beam was no longer centered on the PZT2 mirror and was near the edge.  This was causing us to clip at the BS aperture.

We took some deep breaths and tried to figure out what we did that could have messed things up.

Jenne noticed that we had moved slightly on the PSL QPDs, so she adjusted the PSL output pointing to re-aquire the previous pointing, and realigned the MC.  This had a very small positive affect, but not nearly enough to compensate for whatever happened.

We spent some more time trying to track down what might have changed, but were unable to come up with anything conclusive.  We then decided to see if we could recover things by just adjusting the PZT input steering mirrors.  We couldn't; recentering at PRM, BS, ITMY, and ETMY was moving us off of PR3.

Jenne suggested we look at the spot positions on the MMT mirrors.  I had checked MMT1 and it looked ok, but we hadn't looked at MMT2.  When we checked MMT2 we noticed that we were also off in yaw.  This made us consider the possibility that the BS table had twisted, most likely when I was securing the moved mass.  Sure enough, when I manually twisted BS table, by grabbing it with my hand, very little force would cause the input beam to walk much of the way across PZT2, more than accounting for the offset.  The effect was also very clearly hysteretic as well; I could twist the table a little and it would stay in the new position.

At this point we had fucked things up enough that we realized that we're basically going to have to walk through the whole alignment procedure again, for the third time this vent.  We were able to recover the PRM retro-reflection a bit, but the tip-tilts have drifted in pitch (likely again because of the table levelling).  So we're going to have to walk through the whole procedure systematically again.

Lessons learned:  Many things are MUCH more sensitive than I had been assuming.  The tip-tilts are of course ridiculous, in that lightly touching the top or bottom of the mirror mount will move it by quite a lot in pitch.  The tables are also much more sensitive than I had realized.  In particular, tightening screws can twist the table hystereticly by milliradians, which can of course completely loose the pointing.  We need to be a lot more careful.

Assuming the table hasn't moved too much we should be able to recover the alignment by just adjusting the PZTs and tweaking the pitch of the tip-tilts.  At least that's the hope.    No more touching the table.  No more leveling.  Hopefully we can get this mostly done tomorrow morning.

  7673   Tue Nov 6 16:38:37 2012 jenne, jamie, ayaka, manasaUpdateAlignmentAlignment back under control again

We had a big alignment party early this morning, and things are back to looking good.  We have been very careful not to bump or touch tables any more than necessary.  Also, we have removed the apertures from the BS and PRM, so there are no more apertures currently left in the chambers (this is good, since we won't forget).

We started over again from the PZTs, using the PRM aperture and the freestanding aperture in front of PR2, to get the height of the beam correct.  We then moved PZTs to get the beam centered on BS, ITMY, ETMY.  We had to do a little poking of PR2 (and PR3?) to get pitch correct everywhere.

We then went to ETMX to check beam pointing, and used BS to steer the beam to the center of ETMX.  We checked that the beam was centered on ITMX.

We went through and ensured that ITMX, ITMY, PRM, SRM are all retroreflecting.  We see nice MICH fringes, and we see some fringes (although still not so nice...) when we bring PRM and SRM into alignment.

We checked the AS path (with only MICH aligned), and made sure we are centered on all of the mirrors.  This included steering a little bit on the mirrors on the OMC table, in yaw.  Initially, AS was coming out of the vacuum, but hitting the side of the black beam tube.  Now it gets nicely to the table.

For both AS and REFL, we made sure there is no clipping in the OMC chamber.

I recentered the beams for AS and REFL on their respective cameras.

IPPOS was centered on the QPD.  This involved moving the first out-of-vac steering mirror sideways a small amount, since the beam was hitting the edge of the mirror.  IPANG was aligned in-vac, and has been centered on the QPD.

Right now, Manasa, Jamie and Ayaka are doing some finishing touches work, checking that POY isn't clipping on OM2, the second steering mirror after the SRM, and they'll confirm that POX comes out of the chamber nicely, and that POP is also still coming out (by putting the green laser pointer back on that table, and making sure the green beam is co-aligned with the beam from PR2-PR3.  Also on the list is checking the vertex oplevs.  Steve and Manasa did some stuff with the ETM oplevs yesterday, but haven't had a chance to write about it yet.

  7674   Tue Nov 6 17:07:04 2012 jamieUpdateAlignmentAS and REFL

AS: tmp6oTENk.png

REFL: tmplamEtZ.png

  7675   Tue Nov 6 17:22:51 2012 Manasa, JamieUpdateAlignmentAlignment- POY and oplevs

Right now, Manasa, Jamie and Ayaka are doing some finishing touches work, checking that POY isn't clipping on OM2, the second steering mirror after the SRM, and they'll confirm that POX comes out of the chamber nicely, and that POP is also still coming out (by putting the green laser pointer back on that table, and making sure the green beam is co-aligned with the beam from PR2-PR3.  Also on the list is checking the vertex oplevs.  Steve and Manasa did some stuff with the ETM oplevs yesterday, but haven't had a chance to write about it yet.

We were trying to check POY alignment using the green laser in the reverse direction (outside vacuum to in-vac) . The green laser was installed along with a steering mirror to steer it into the ITMY chamber pointing at POY.

We found that the green laser did follow the path back into the chamber perfectly; it was clipping at the edge of POY. To align it to the center of POY (get a narrower angle of incidence at the ITMY), the green laser had to be steered in at a wider angle of incidence from the table. This is now being limited by the oplev steering optics on the table. We were not able to figure out the oplev path on the table perfectly; but we think we can find a way to move the oplev steering mirrors that are now restricting the POY alignment.

The oplev optics will be moved once we confirm with Jenne or Steve.

 

[Steve, Manasa]

We aligned the ETM oplevs yesterday. We confirmed that the oplev beam hit the ETMs. We checked for centering of the beam coming back at the oplev PDs and the QPDsums matched the values they followed before the vent.

Sadly, they have to be checked once again tomorrow because the alignment was messed up all over again yesterday.

  7677   Wed Nov 7 00:10:38 2012 Jenne UpdateAlignmentAlignment- POY and oplevs. photos.
Can we have a drawing of what you did, how you confirmed your green alignment as the same as the IR (I think you had a good idea 
about the beam going to the BS...can you please write it down in detail?), and where you think the beam is clipping? Cartoon-level, 20 
to 30 minutes of work, no more. Enough to be informative, but we have other work that needs doing if we're going to put on doors 
Thursday morning (or tomorrow afternoon?).

The ETMs weren't moved today, just the beam going to the ETMs, so the oplevs there shouldn't need adjusting. Anyhow, the oplevs I'm 
more worried about are the ones which include in-vac optics at the corner, which are still on the to-do list.

So, tomorrow Steve + someone can check the vertex oplevs, while I + someone finish looking briefly at POX and POP, and at POY in 
more detail.

If at all possible, no clamping / unclamping of anything on the in-vac tables. Let's try to use things as they are if the beams are getting to 
where they need to go.  Particularly for the oplevs, I'd rather have a little bit of movement of optics on the out-of-vac tables than any 
changes happening inside.

I made a script that averages together many photos taken with the capture script that Rana found, which takes 50 pictures, one after 
another. If I average the pictures, I don't see a spot. If I add the photos together even after subtracting away a no-beam shot, the 
picture us saturated and is completely white. I'm trying to let ideas percolate in my head for how to get a useful spot. 
  7678   Wed Nov 7 07:11:10 2012 ranaUpdateAlignmentAlignment- POY and oplevs. photos.

The way to usually do image subtraction is to:

1) Turn off the room lights.

2) Take 500 images with no beam.

3) Use Mean averaging to get a reference image.

4) Same with the beam on.

5) Subtract the two averaged images. If that doesn't work, I guess its best to just take an image of the green beam on the mirrors using the new DSLR.

  7679   Wed Nov 7 09:09:02 2012 SteveUpdateAlignmentAlignment-
PRM and SRM  OSEM LL 1.5V are they misaligned?
Attachment 1: 9amNov7w.png
9amNov7w.png
  7682   Wed Nov 7 15:17:15 2012 SteveUpdateAlignmentsteering option with pico motor?
We have two ready for vacuum 1.5" mirror mounts with pico motors in our hands. 


 
Attachment 1: IMG_1795.JPG
IMG_1795.JPG
  7683   Wed Nov 7 15:51:44 2012 JenneUpdateAlignmentJamie's tip tilt proposal

Steve's elog 7682 is in response to the conversation we had at group meeting re: Jamie's proposed idea of re-purposing the active tip tilts.

What if we use the active TTs for the PR and SR folding mirrors, and use something else (like the picomotors that Steve found from the old days) for our input steering?

  7684   Wed Nov 7 17:20:01 2012 jamieUpdateAlignmentJamie's tip tilt proposal

Quote:

Steve's elog 7682 is in response to the conversation we had at group meeting re: Jamie's proposed idea of re-purposing the active tip tilts.

What if we use the active TTs for the PR and SR folding mirrors, and use something else (like the picomotors that Steve found from the old days) for our input steering?

I think we will still need two active steering mirrors for input pointing into the OMC, after the SRC, so I think we'll still need two of the active TTs there.

My thought was about using the two active TTs that we were going to use as the input PZT replacements to instead replace the PR2/3 suspensions.  Hysteresis in PR2/3 wouldn't be an issue if we could control them.

With static input pointing, ie. leaving PZT2/3 as they are, I think we could use PRM and PR2/3 to compensate for most input pointing drift.  We might have to deal with the beam in PRC not being centered on PRM, though.

Koji's suggestion was that we could replace the PZTs with pico-motors.  This would give us all the DC input pointing control we need.

So I guess the suggestion on the table is to replace PZT1/2 with pico-motor mounts, and then replace PR2/3 with two of the active tip-tilts.  No hysteresis in the PRC, while maintaining full input pointing control.

  7686   Wed Nov 7 23:22:45 2012 ranaUpdateAlignmentJamie's tip tilt proposal

 With Picos, we lose the ability to dither the input beam as well as align the beam with the IFO locked. And the active TT will still have hysteresis, but also actuators. Once in vacuum, I'm not sure how we adjust them - what's the error signal for PR2/PR3 ?

If the interferometer is aligned, why not just pump down now? I'm not sure that we have evidence of TT hysteresis issues once people stop touching them.

  7689   Thu Nov 8 20:11:54 2012 JenneUpdateAlignmentAS steering moved out of POY's way, 2 green beams onto PSL table

[Jenne, Jamie, Manasa, Ayaka]

 

Flipped mount of OM2, moved OM2 behind POY pickoff so we're out of the way of POY.  Adjusted and recovered rest of AS path.

We found that IPANG was not on its photodiode, but determined that it was centered on all of the in-vac mirrors, and that it was just a little bit of steering on the ETMY end out-of-vac table that needed to be done.

Got green flashes in Yarm, moved down periscope to the north by ~1 inch in order to get y green out to PSL table.  This also involved moving the steering mirror on the IOO table immediately after the down periscope to match.  We measured the MC spot positions before and after touching the periscope, and there was no significant change. 

Aligned X green to X arm (centered on ITMX, ETMX, although no flashes since we didn't move ETMX's biases around), then made sure it was centered on all of its steering mirrors, and came out of the vacuum.

Manasa took photos of all test mass chambers and the BS chamber, so we can keep up-to-date CAD drawings. 

Oplevs and IPPOS/IPANG are being centered as I type.  Manasa and Ayaka are moving the lens in front of IPANG such that we have a slightly larger beam on the QPD.

 

In the morning, Jamie is going to put apertures back on 2 of the suspended mirrors for one last check that moving things on the IOO table didn't do anything bad, but since the AS and REFL beams on those cameras didn't move significantly, we think things are fine. 

Heavy doors go on in the morning, and access connector at ~1pm, if not before lunch.  Then Steve will start pumping early Monday morning!  Hooray!

 

PS, for reference,

AS: AS_8Nov2012.png

REFL: REFL_8Nov2012.png

  7690   Thu Nov 8 20:54:08 2012 Manasa, AyakaUpdateAlignmentReconfirming on IPPOS, IPANG and oplevs centering

Quote:

" We found that IPANG was not on its photodiode, but determined that it was centered on all of the in-vac mirrors, and that it was just a little bit of steering on the ETMY end out-of-vac table that needed to be done."

Manasa took photos of all test mass chambers and the BS chamber, so we can keep up-to-date CAD drawings. 

Oplevs and IPPOS/IPANG are being centered as I type.  Manasa and Ayaka are moving the lens in front of IPANG such that we have a slightly larger beam on the QPD.

 

The lens in front of IPANG on the out-of-vac table was moved to get a larger beam giving reasonable signals at the QPD.

IPPOS did not need much adjustment and was happy at the center of the QPD.

All oplevs but the ETMY were close to the center. I had to move the first steering mirror about half an inch on the out-of-vac table to catch the returning oplev beam from ETMY and direct it to the oplev PD.

* We have taken reasonable amount of in-vac pictures of ETM, ITM and BS chambers to update the CAD drawing.

 

  7692   Fri Nov 9 08:11:57 2012 SteveUpdateAlignmentnothing moved - all good

 Oplevs and IP ANG are still centered. Why  do the SRM and PRM move 5X  more ?  I could not check the sensing voltages because the computer failed.

AS and REFL are looking the same as last night.

ALL LOOKING GOOD!

 

Attachment 1: opsingGOOD.png
opsingGOOD.png
Attachment 2: op8h.png
op8h.png
Attachment 3: 8amF.png
8amF.png
Attachment 4: keepfailing.png
keepfailing.png
  7715   Thu Nov 15 03:09:08 2012 JenneUpdateAlignmentNo good progress, many options
I didn't make any concrete progress today. AS and REFL cameras are in place, and Manasa has put ND 0.5 filters on both. I used a 
camera to look at the back of the Faraday, and aligned PRM such that it was retroreflecting, and then tried to align ITMY to have once 
fringes with the PRM at that place. I failed in this, since the AS beam on the AS table was starting to dall off the first mirror on the table. 
I then restored all the suspensions to where they were before I started touching them today. 

I moved ETMY face camera so that it is looking at the front of the black glass, but it's hard to tell where the beam is.  I was thinking 
about setting up a temporary camera to look at the back of ITMY to help guide PZT steering, but I haven't done this yet. 

Koji and I then talked about the several different options I have for references, and how many different knobs I  can turn. I'm sleeping 
on it for now, and hopefully I'll have more insight on what to do tomorrow. 
  7720   Sat Nov 17 03:30:13 2012 Den, AyakaUpdateAlignmentred in arms

We aligned accurately 00 green in yarm, changed voltage on PZT2 to see red flashing at TRY at the normalized level 0.2-0.3. The plan was to lock yarm using POY11 and green from other side, maximize red TRY by adjusting PZT2. But POY11 does not go out of the vacuum, so we adjusted TRY by flashing. 2 DOFs of PZT2 is not enough to match 4 DOFs of red beam so we adjusted both PZT2 and cavity mirrors. TRY flashing is 0.5-0.6 and green is still locking to 00 though its transmission is not maximized. We'll fix it later by adjusting input green beam.

Next we wanted to get red beam on TRX PD. Beam steering was done by BS only. We misaligned BS in pitch and excited BS angle motion by 1000 counts. We could see red beam moving on the wall of ETMX chamber. We moved it to ETMX mirror frame, estimated position of the mirror center and moved BS to this position. The beam should be approximately in the middle. For now we can not see red beam on the camera at ETMX table, more work is needed.

  7721   Sat Nov 17 18:02:14 2012 DenUpdateAlignmentred in arms

Quote:

POY11 does not go out of the vacuum

 It does but slighty low and does not get on mirrors. We need to change optic mounts to adjust the height. Red is flashing in yarm at 00 and 10 modes. TRY is ~0.4-0.5.

I've adjusted BS angle, camera and TRX PD at ETMX table so I can see red flashing at 03 mode while green is locked to 00 and its transmission is maximized. I thought that by adjusting BS angle, I will be able to align red to 00 not disturbing green, but this was not the case. Maximum TRX I could get was 0.1. I've adjusted POX to get into PD and I can see PDH signal though I can't lock as cavity is still misaligned for red.

  7722   Sat Nov 17 22:50:17 2012 KojiUpdateAlignmentred in arms

You have constraints for the IR beams (i.e. one PZT and one BS for 8 dofs), so now you need to align the arms for the input IR beams.
The PZT and BS should be aligned so that you have the beam spots as center as possible with the above restrictions.

Then realign end greens for the given arm alignment. You can replace the mounts if necessary to align the end green.
Even if you lose the coarse alignment of the green, realignment is not difficult as you know now

Quote:

Quote:

POY11 does not go out of the vacuum

 It does but slighty low and does not get on mirrors. We need to change optic mounts to adjust the height. Red is flashing in yarm at 00 and 10 modes. TRY is ~0.4-0.5.

I've adjusted BS angle, camera and TRX PD at ETMX table so I can see red flashing at 03 mode while green is locked to 00 and its transmission is maximized. I thought that by adjusting BS angle, I will be able to align red to 00 not disturbing green, but this was not the case. Maximum TRX I could get was 0.1. I've adjusted POX to get into PD and I can see PDH signal though I can't lock as cavity is still misaligned for red.

 

  7723   Mon Nov 19 15:12:52 2012 JenneUpdateAlignmentYarm locked IR

Quote:

Quote:

POY11 does not go out of the vacuum

 It does but slighty low and does not get on mirrors. We need to change optic mounts to adjust the height. Red is flashing in yarm at 00 and 10 modes. TRY is ~0.4-0.5.

I've adjusted BS angle, camera and TRX PD at ETMX table so I can see red flashing at 03 mode while green is locked to 00 and its transmission is maximized. I thought that by adjusting BS angle, I will be able to align red to 00 not disturbing green, but this was not the case. Maximum TRX I could get was 0.1. I've adjusted POX to get into PD and I can see PDH signal though I can't lock as cavity is still misaligned for red.

 [Ayaka, Jenne]

We put the POY beam onto the POY PD.  The Yarm is currently locked on IR with ~0.65 transmission.

 

  7772   Sat Dec 1 00:24:37 2012 Den, AyakaUpdateAlignmentBS chamber

Today at 11:13 AM the stack of invacuum BS table was kicked and IFO misaligned. We adjusted PZT2 voltage by ~20 V in yaw such that IPPOS was restored. Then we could lock arms.

push.png

  7773   Sat Dec 1 13:56:38 2012 ranaUpdateAlignmentBS chamber

 

 Whoever was working around the BS chamber at 11 AM on Friday should admit it now and take the punishment.

For those of you who like to do work on the interferometer without reporting it in the elog because you think that what you did doesn't affect anything, this is your example of how our time can be wasted by such laziness.

  7776   Mon Dec 3 07:40:00 2012 SteveHowToAlignmenthow was the BS chamber misalinged

Quote:

 

 Whoever was working around the BS chamber at 11 AM on Friday should admit it now and take the punishment.

For those of you who like to do work on the interferometer without reporting it in the elog because you think that what you did doesn't affect anything, this is your example of how our time can be wasted by such laziness.

 I'm taking full responsibility for this action and I told them after lunch Friday.

 

HOW NOT TO:

The BS isolation stack  supported by two beam tubes and they can pivot around the pivot point.

Attachment 1: BSsupport.jpg
BSsupport.jpg
  7784   Tue Dec 4 18:53:50 2012 AyakaUpdateAlignmentBS chamber

BS chamber seemed to be kicked again around 10:00 am today.

I moved PZT mainly in YAW and locked both arms. I adjusted the beam to be almost on the center of both ETM by sights.

BSchamb1204.pdf

  7795   Thu Dec 6 02:55:46 2012 DenUpdateAlignmentc1ass

Today I've set c1ass model to improve alignment of X and Y arms. I've added all measured parameters to ASS scripts. I've also added a script to c1ass.adl that downloads calculated OFFSETs to corresponding ASC filter banks and blocks outputs. It should be called after alignment convergence.

XARM phase rotation and sensing matrix

Demodulator Phase rotation, degrees
ETM_P_T -5
ETM_Y_T -10
ITM_P_T -62
ITM_Y_T 163

                                                           

I-quadrature ETM_PIT ETM_YAW ITM_PIT ITM_YAW
ETM_P_T

1.0000  

-0.6116 -0.560 0.5660
ETM_Y_T -0.1600 1.0000 0.2310 -0.3979
ITM_P_T -0.0794 0.4960 1.0000 -0.8791
ITM_Y_T 0.0624 -0.3903 -0.4787 1.0000

 

Output gains were (-0.5, 0.5, -0.25, -0.25). XARM Gain was set to 0.5.

xarm_ass.png

YARM phase rotation and sensing matrix

Demodulator Phase rotation, degrees
ETM_P_T 10
ETM_Y_T 0
ITM_P_T 107
ITM_Y_T -35

 

I-quadrature ETM_PIT ETM_YAW ITM_PIT ITM_YAW
ETM_P_T

1.0000  

0.3899 -0.515  -0.0309
ETM_Y_T 0.1017 1.0000 -0.3143 -0.5269
ITM_P_T -0.3505 0.0565 1.0000 -0.0945
ITM_Y_T -0.2085 -0.3607 0.6042 1.0000

Output gains were (-0.25, 0.25, 0.7, -0.7). YARM Gain was set to 0.8.

yarm_ass.png

  7796   Fri Dec 7 00:08:39 2012 ranaUpdateAlignmentc1ass

 

 This looks like a good performance tuning for these. It would be good if you can codify this procedure in the wiki so that even unexperienced people can tune up the system after reboots or vacuum work.

Is it possible to have some python scripts automatically measure and set the phases and matrices? If so, can we also run them iteratively so that after the second run we can confirm that they have converged? Then the script can output a short report of numbers telling us how well the system is now tuned.

I suppose that there is also a similar system possible to align the arms in a continuous way; i.e. low level drives and very low bandwidth. Also something fast / slow for the the DRMI.

  7797   Fri Dec 7 02:02:23 2012 DenUpdateAlignmentc1ass

I suppose that there is also a similar system possible to align the arms in a continuous way; i.e. low level drives and very low bandwidth. Also something fast / slow for the the DRMI.

 c1ass was really useful today when we slowly aligned PZT and servo kept arms aligned to the input beam. I think it is possible to automate phase and matrix measurements. DRMI servo will be very useful.

Today I tried to investigate the mode in PRCL and MICH. I locked them but power build-up was only 27. The beam on the POP camera looked like interference of 00 mode and a long strip of fringes. (I wanted to make videocaptures but script is not working - the problem is that it is looking for /usr/lib/*.so.4 libraries but they were updated to *.so.5, I made a few links .so.4 -> .so.5 but this kept going for many libraries, so this should be fixed in a better way). 

We looked at PRM and BS faces and they had the same shape - interference of a circle with a strip. There were also a lot of bright spots all over the frames. Loops were closed and circle was not moving. Strip was oscillating at ~1Hz and also its position significantly changed with alignment. Looking at PRM face camera we made a conclusion that the length of the strip is ~5 cm and width ~1cm. Interesting that strip has plenty of power - approximately 10 times of transmitted beam when cavity is not locked. As a result POYDC was oscillating at the same frequency as a strip.

  7816   Wed Dec 12 16:52:12 2012 JenneUpdateAlignmentPR2_face, PR3_back cameras in place

I have setup cameras looking at the back of PR3 (through the north viewport on the MC chamber) and the face of PR2 (through the north viewport on the ITMX chamber). We would like a view of the face of PR3, but that isn't possible without placing another in-vac mirror.  The best we can do is the current PRM_BS camera setup, which sees a small portion of the PR3 face.  Most of the face is obscured by the PRM itself. 

I have taken images with the PRM misaligned.  The spot near the top of PR2 is the first reflection from the pitch-misaligned PRM, so it should be ignored for the purposes of trying to see the straight-shot, no PRM beam.

Images are taken with my videocapture50 script, in ..../scripts/general/videoscripts.  This takes 10 sets of 50 images and saves them.  Then ImageBkgndSubtractor.m located in the same folder takes the images (you must edit the beginning of the script to tell it where the images are), averages the noBeam images (PSL shutter closed), and averages the withBeam images, and subtracts them.  Results below:

PR2_face_12Dec2012_SpotImage.pngPR2_face_12Dec2012_SpotImage_pixelsTimes3.png

PR3_back_12Dec2012_SpotImage.pngPR3_back_12Dec2012_SpotImage_pixelsTimes3.png

  7839   Mon Dec 17 14:45:01 2012 JenneUpdateAlignmentVideos with PRMI locked

[Jamie, Jenne]

Koji and Jamie locked the PRMI, and then Jamie and I took some videos. 

Video 1:   https://www.youtube.com/watch?v=jszTeyETyxU shows the face of PR2.

Video 2:   https://www.youtube.com/watch?v=Tfi4I4Q3Mqw shows the back of PR3, the face of PR2, as well as REFL and AS.

Video 3:   https://www.youtube.com/watch?v=bLHNWHAWZBA is the camera looking at the face of PRM and (through a viewing mirror) BS.

 

If you watch video 1, you'll see how large the beam gets on the face of PR2.  The main spot, where the straight-through, no-cavity beam is, is a little high of center.  The rest of the inflated beam swirls around that point.

Video 2 shows the same behavior, but you also see that we're much too high on PR3, and too close to the right (as seen on the video) side.

Video 3 is very disconcerting to me.  The main, stationary beam spot seems nicely centered, but the resonant beam, since it inflates and gets big, is very close to the right side of the PRM (as seen on the video). 

It wouldn't surprise me if, were we able to quantify the beam clipping loss on PR3 and PRM, the clipping were the reason we have a crappy PRC gain.  This doesn't explain why we have such a weird inflated beam though.

  7852   Tue Dec 18 16:37:17 2012 JamieUpdateAlignmentPost vent, pre door removal alignment

[Jenne, Manasa, Jamie]

Now that we're up to air we relocked the mode cleaner, tweaked up the alignment, and looked at the spot positions:

mcspot_post_vent.pdf

The measurements from yesterday were made before the input power was lowered.  It appears that things have not moved by that much, which is pretty good.

We turned on the PZT1 voltages and set them back to their nominal values as recorded before shut-down yesterday.  Jenne had centered IPPOS before shutdown (IPANG was unfortunately not coming out of the vacuum).  Now we're at the following value: (-0.63, 0.66).  We need to calibrate this to get a sense of how much motion this actually is, but this is not insignificant.

 

  7877   Mon Jan 7 00:08:16 2013 JenneHowToAlignmentIn-vac plan

List of things to do, in order:

* Remove BS heavy door.  Steve, please remove the BS door as soon as you have enough people to do so.  I will be a little late, since I have a dentist appointment, but please don't wait for me.  Jamie and Manasa can help you.  Put on a light door.

* Remove MC light doors, make aluminum foil tube (not light access connector, yet).

* Open laser shutter, lock PMC. (Required slight tweaking of input steering.) Confirm power level into vacuum <100mW.

* Lock MC and check spot positions of MC (quickly.  this shouldn't take all day, hopefully).

-------------------------------  End of work for Monday.  See following elog ------------------------------------------------

 

* Move TT1 to be as close as possible to the location indicated on the diagram, then align it. 

         * Make sure beam out of Faraday is hitting the center of the optic.

         * Make sure beam reflected off of TT1 hits center of PZT2.  Only use actuators for the final alignment, then confirm that they aren't close to the edge of their ranges.

         * Lock down TT1 with dog clamps.

* Put light access connector on MC.

* Swap PZT2 out with TT2.  Should be at correct spot, according to diagram, and beam should be hitting center of optic.  Alignment only to the ~few degree point here.

* Re-level BS table.

* Fix oplevs that need fixing.  (Manasa should have the plan on one of the diagrams).

* Put target on PRM cage.

* Align TT2 so that beam goes through PRM target.

* Open ITMX heavy door. (Probably Tuesday morning).

* Place freestanding target in front of PR2.  Ensure TT2 is aligned to go through PRM target, and hit center of PR2.  Again, save actuators for fine-tuning.

At this point, I think we should (temporarily) install one of the G&H mirrors as a flat mirror facing the PRM, and see if we can lock that cavity using REFL.  We will want to have already created a model for this case, to compare our observations to.  Or we could align the full PRMI, and try to lock that in air.

 

 

  7878   Mon Jan 7 16:45:30 2013 JenneUpdateAlignmentRisers to bring TTs to correct beam height are wrong

[Jenne, with backup from Koji and Steve]

Short version:

TT1 was installed without a riser, optic is too low, riser we have doesn't fit, cannot proceed with alignment.  Sadface.

Long version:

I had gotten to the point of checking that the beam coming out of the Faraday was hitting the center of TT1, when I realized that we had forgotten to install the risers.  The TTs are designed for 4" beam height, but we have a beam height of 5.5" in-vac.  This means that the beam out of the Faraday was hitting the top of the optic / the optic holder.

Steve showed me where all of the active TT equipment is stored (down the X arm, almost all the way to the flow bench...there is a plastic tub full of baked items (individually wrapped and bagged)), and I got one of the 1.5" risers.

Upon opening the riser package, and comparing it with the base plate of the active tip tilt, the screw holes don't match!

TT1_7Jan2013_BasePlateAndRiserHoleMismatch.JPG

It looks like for the passive tip tilts, we had holes machined at the far corners of the base plate, then had these risers made.  You can see in the photo of SR3 below that the original holes are there, but we are using 1/4-20 holes at the far corners of the base plate.

SR3_7Jan2013_ExtraHoleMachinedAtCorner.JPG

Unfortunately, without checking the base plate, I had asked Steve to get 4 more of the same risers we used for the passive tip tilts.  So, now the base plate holes and the riser holes don't match up.  In a perfect world, we would have installed the risers on the TTs as soon as they were baked and ready, and would have discovered this a while ago....but we don't live in that world.

 The reason we had originally chosen to put the new 1/4-20 holes on the corners of the passive tip tilts was so that when we tightened the screws, we wouldn't bend the base plate, due to the groove at the bottom of the base plate being directly under the screws.  Since the new aLIGO TT base plates have the groove underneath going the opposite direction, we didn't need to move the holes to the corners.

Also, you can't really see this from the photos, but the active TT base plate is slightly longer (in the beamline direction) than the riser, but only by a little bit.  Koji is currently trying to measure by how much from the CAD drawings.

Also, also, because of the way TT1 will hang off the table, I'm concerned about the underneath groove on the riser being the direction it is.  I'm concerned that the grooved part will be what wants to touch down on the back corner of the table, such that either the TT is insufficiently supported, or it is tilting backwards.  Neither of these will be acceptable.

I propose that we re-make the risers quickly.  We will have the holes match the active TT base plate, the size of the riser should match the size of the active TT base plate, and the underneath groove should be perpendicular to the way it is in the current version.

  7883   Tue Jan 8 17:54:34 2013 JenneUpdateAlignmentRisers to bring TTs to correct beam height are in use

 

 [Jenne, EricQ, Nic, MattA]

* TT1 is in place, aligned so beam hits center of TT1, hits center of MMT1 (used pitch biases to finish pitch).

      * Riser installed, dogged down with 1 dog.

      * TT1 sitting on top of riser, 3 dogs holding TT to table, with riser squished in between.

* IOO table leveled.

      * Almost all of the weights on the IOO table were just sitting there, not screwed down!  One didn't even have a screw, 3 had screws, but they were totally loose.  2 of those screws were in as far as they could go, but they weren't holding the weight.  This means the screw was too long, and should have been replaced (which I did today).  Just because the existing screw was too long, doesn't mean it should be left as-is.  Everything in the chambers must be tightly clamped down, as soon as work on that item is complete!  Anyhow, after finalizing the leveling, I tightened down all of the weights on the IOO table.

* MMT1 tweaked so beam hits center of MMT2. 

* MMT2 tweaked so beam hits center of PZT2.

* Light access connector installed.

 

Sadface notes:

* I dropped a Class B golden-colored 3/16 allen key to the bottom of the IOO chamber.  I can't see it, but Nic thinks he might be able to see it with a mirror, from the BS chamber.  We should look for it when we look for the IR card that is still down there.

* We have an ant in the IOO chamber.  Unfortunately my hands were on the TT1 optic holder ring when I saw it, so I couldn't dash quickly enough to grab it.  I saw it run over the side of the table, and down, but looked under the table and couldn't find him.  Not so good, but I don't know what to do about it right now.  If anyone sees it, get it out please.

  7886   Wed Jan 9 18:59:01 2013 JenneUpdateAlignmentTT2 installed, PRM oplev layout changed

[Jenne, Manasa]

PZT2 was removed from the BS table, and packed away in a foil-lined plastic box.

PRM oplev path has been altered, including installation of a 3rd mirror, to accommodate TT2, which is larger than PZT2.

      * Unfortunately, PR3 is a few mm more north than is indicated in the CAD drawing, so I wasn't able to place the oplev mirrors exactly as Manasa indicated in elog 7815

      * We came up with a different layout. Photos were taken.  We will need to confirm that the IPPOS, AS, and GreenX beams all clear past the oplev mirrors, but by imagining straight lines between mirrors for those beams, I think we should be okay.  but we must confirm when we have real beams.

TT2 was installed, according to the placement in the diagram.   Dogged down just as TT1 - one dog for the riser, 3 dogs for the TT base which also squish the riser.  You should be able to see this in the photos. Without having installed the PRM target, it looks like the input beam is hitting pretty close to the PRM's center.  Tomorrow Jamie The Tall can install the PRM target for us so we can confirm.

 

Photos - I'm posting them on Picasa here.  The new camera, and the fact that you can rotate the viewfinder, is amazing for overhead in-chamber photos.  Seriously, it's much easier to take useful photos.  It's great.

 

Tomorrow:

We remove the ITMX door first thing.  If Steve isn't here, we'll ask Koji or Bob to help us with the crane. 

First thing on the alignment list is to finalize TT2's pointing.  Put a target in front of PR2, put on the PRM target, etc, etc.  We're basically back to the same alignment procedure as we've been doing the last few vents.

 

Item for meditation:

Do we trust ourselves, or do we want to think about installing a 'bathroom mirror' so we can see the face of PR3 while we are pumped down?

  7888   Thu Jan 10 12:22:36 2013 JenneUpdateAlignmentTT matrix is funny

Quote:

* TT1 is in place, aligned so beam hits center of TT1, hits center of MMT1 (used pitch biases to finish pitch).

 I had asked Q to write this down on a piece of paper, but then I forgot to transcribe it into the elog....

The TT screen matrix, at least for TT1, is flipped or something.  When Eric moved the pit slider, the optic moved in yaw, and vice versa. 

We need to fix this, but for now, here's the situation when TT1 was pointed correctly at MMT1:

                       PIT    YAW

TT1 Pit slider     |  1000   1000  | --->   700 UL

     0             | -1000   1000  | --->   700 LL

TT1 Yaw slider     |  1000  -1000  | --->  -700 UR

    0.7            | -1000  -1000  | --->  -700 LR

 

The confusing thing is that Koji and I confirmed (by plugging in the correct cable to the correct sensor) that "UL" on the screen goes to the UL coil, and the same for the other 3 coils.  This needs investigation / fixing.

  7890   Thu Jan 10 15:30:33 2013 JenneUpdateAlignmentTT2 pins swapped, ITMX door open

 

[Bob, Manasa, Jenne]

We opened the ITMX heavy door.  Before getting too far, we realized that we had to do the fancy pin swapping before we can activate TT2.  So....

[Nic, Jenne]

We followed the instructions in elog 7869, and the associated Picasa album, and swapped the pins for the in-vac connector that will go to TT2.  Pretty easy, since the procedure was already well documented.

We then looked at the beam location on PR2, and the beam is ~2 inches up and to the left (as viewed from the front) from the center of the optic.  This is very easily correctable with the actuators, so we're leaving TT2 as it is.

  7893   Fri Jan 11 17:32:10 2013 ManasaUpdateAlignmentTT2 connections

 

 Manasa, Jenne

We started off to try and get TT2 working. We used the cables Jamie had already prepared while working on TT1 and used them to connect TT to the channels in 1Y3.

There were sma cable connectors already running between the channels 5-8 on the board to the UL,LL,UR and LR. Triggering the UL LL UR LR matrix on epics did not show any analog voltage at the output analog channels on the board. Talking to Jamie over phone, we inferred  that the  SMA cables that were already left connected corresponded to channels assigned for TT4 in epics.  So we set the connections right and could see analog voltage outputs corresponding to epics triggers.

We connected the ribbon cables running from the board to the TT. But changing pitch and yaw did not do anything to the TT2 mirror. We opened the BS door and checked if  the tt cables were connected to the post. We beeped the cable running from the board to TT (we also traced the cable's trail through the cable rack pile from 1Y3 to BSC). Using a function generator at the board end of the cable, we could not observe anything at the TT end of the cable.

We ran out of options on what can be done next and closed the doors. We hope Jamie can fix the problem once he returns next week.

  7894   Fri Jan 11 19:12:20 2013 KojiUpdateAlignmentTT2 connections

Was the connection between the feedthrough (atmosphere side) and the connector on the optical table confirmed to be OK?

We had a similar situation for the TT1. We found that we were using the wrong feedthrough connector (see TT1 elog).

  7896   Mon Jan 14 10:12:09 2013 JenneUpdateAlignmentTT2 connections

Quote:

Was the connection between the feedthrough (atmosphere side) and the connector on the optical table confirmed to be OK?

We had a similar situation for the TT1. We found that we were using the wrong feedthrough connector (see TT1 elog).

 The major problem that Manasa and I found was that we weren't getting voltage along the cable between the rack and the chamber (all out-of-vac stuff).  We used a function generator to put voltage across 2 pins, then a DMM to try to measure that voltage on the other end of the cable.  No go.  Jamie and I will look at it again today.

  7897   Mon Jan 14 12:08:39 2013 jamieUpdateAlignmentTT2 connections

Quote:

Quote:

Was the connection between the feedthrough (atmosphere side) and the connector on the optical table confirmed to be OK?

We had a similar situation for the TT1. We found that we were using the wrong feedthrough connector (see TT1 elog).

 The major problem that Manasa and I found was that we weren't getting voltage along the cable between the rack and the chamber (all out-of-vac stuff).  We used a function generator to put voltage across 2 pins, then a DMM to try to measure that voltage on the other end of the cable.  No go.  Jamie and I will look at it again today.

Everything was fine.  Apparently these guys just forgot that the cable from the rack to the chamber flips it's pins.  There was also a small problem with the patch cable from the coil driver that had flipped pins.  This was fixed.  The coil driver signals are now getting to the TTs.

Investigating why the pitch/yaw seems to be flipped...

  7901   Tue Jan 15 19:26:35 2013 jamieUpdateAlignmentAdjustment of active TTs and input alignment

[Jamie, Manasa, Jenne]

We started by verifying that the tip-tilts were getting the correct signals at the correct coils, and were hanging properly without touching.

We started with TT2.  It was not hanging freely.  One of the coils was in much further than the others, and the mirror frame was basically sitting on the back side yaw dampers.  I backed out the coil to match the others, and backed off all of the dampers, both in back and the corner dampers on the front.

Once the mirror was freely suspended, we borrowed the BS oplev to verify that the mirror was hanging vertically.  I adjusted the adjustment screw on the bottom of the frame to make it level.  Once that was done, we verified our EPICS control.  We finally figured out that some of the coils have polarity flipped relative to the others, which is why we were seeing pitch as yaw and vice-versa.  At that point we were satisfied with how TT2 was hanging, and went back to TT1.

Given how hard it is to look at TT1, I just made sure all the dampers were backed out and touched the mirror frame to verify that it was freely swinging.  I leveled TT1 with the lower frame adjustment screw by looking at the spot position on MMT1.  Once it was level, we adjusted the EPICS biases in yaw to get it centered in yaw on MMT1.

I then adjusted the screws on MMT1 to get the beam centered at MMT2, and did the same at MMT2 to get the beam centered vertically at TT2.

I put the target at PRM and the double target at BS.  I loosened TT2 from it's base so that I could push it around a bit.  Once I had it in a reasonable position, with a beam coming out at PR3, I adjusted MMT1 to get the beam centered through the PRM target.  I went back and checked that we were still centered at MMT1.  We then adjusted the pitch and yaw of TT2 to get the transmitted beam through the BS targets as clear as possible.

At this point we stopped and closed up.  Tomorrow first thing AM we'll get our beams at the ETMs, try to finalize the input alignment, and see if we can do some in-air locking.

The plan is still to close up at the end of the week.

  7902   Tue Jan 15 20:00:42 2013 ManasaUpdateAlignmentAdjustment of active TTs and input alignment

 

Just for reference! The changes made to the TT matrix in order to fix the polarity problem:

The old matrix values are mentioned in elog!

 

PIT    YAW                   New                   

Pit slider           |  -100   -100  |  UL  

     0               | -100    100   |  LL

Yaw slider           |  100   -100   |  UR

    0                |  100    100   |  LR

 

 

 

 

 

 

 

  7912   Thu Jan 17 11:01:19 2013 JenneUpdateAlignmentYesterday's alignment work

[Jamie, Jenne, Manasa]

Yesterday's goal was to get the input beam centered on the PRM, the BS and ETMY simultaneously. 

Steve helped us remove the ETMY door first thing in the morning.  We then iterated with TT1, MMT1 and TT2 to try to get the beam centered on all the optics.  We were using MMT1 instead of TT1 for a while, so that we could keep TT1 in the center of its range, so that we had more range to use once we pump down.  Also, at one point, the beam was high on PRM, centered on BS, and high on ETMY, so Jamie poked PR3 a little bit.  This helped, although we closed up for lunch / group meeting soon after, so we didn't finalize any alignment stuff.

We decided to leave the rest of the full IFO alignment alone until after the PRM-flat test.

  7915   Thu Jan 17 19:33:53 2013 ManasaUpdateAlignmentPRM oplev

 We had to work on redesigning the oplev layout in BSC when I found that the positions of the mirrors were clipping IPPOS and the green beam while updating the CAD layout.  

To avoid any clipping, the prm oplev beam is steered into the vacuum by an oplev mirror and out of vacuum through 3 steering mirrors. The table weights had to be moved to allow room for the oplev mirrors. Hence table had to be re-leveled. I will update the CAD drawing with the current position of the mirrors and will reconfirm that the new mirrors are not in the way of any of the beams. In-vac photos are updated in picasa.

  7919   Fri Jan 18 15:08:13 2013 jamieUpdateAlignmentalignment of temporary half PRC

[jenne, jamie]

Jenne and I got the half PRC flashing.  We could see flashes in the PRM and PR2 face cameras.

We took out the mirror in the REFL path on the AP that diverts the beam to the REFL RF pds so that we could get more light on the REFL camera.  Added an ND filter to the REFL camera so as not to saturate.

  7949   Mon Jan 28 21:32:38 2013 jamieUpdateAlignmenttweaking of alignment into half PRC

[Koji, Jamie]

We tweaked up the alignment of the half PRC a bit.  Koji started by looking at the REFL and POP DC powers as a function of TT2 and PRM alignment. 
He found that the reflected beam for good PRC transmission was not well overlapped at REFL.  When the beam was well overlapped at REFL, there was clipping in the REFL path on the AS table.

We started by getting good overlap at REFL, and then went to the AS table to tweak up all the beams on the REFL pds and cameras.
This made the unlocked REFL DC about 40 count. This was about 10mV (=0.2mA) at the REFL55 PD.
This amazed Koji since we found the REFL DC (of the day) of 160 as the maximum of the day for a particular combination of the PRM Pitch and TT2 Pitch. So something wrong could be somewhere.

We then moved to the ITMX table where we cleaned up the POP path.  We noticed that the lens in the POP path is a little slow, so the beam is too big on the POP PD and on the POP camera (and on the camera pick-off mirror as well)
We moved the currently unused POP55 and POP22/110 RFPDs out of the way so we could move the POP RF PD and camera back closer to the focus.  Things are better, but we still need to get a better focus, particularly on the POP PD.

We found two irides on the oplev path. They are too big and one of these is too close to the POP beam. Since it does not make sense too to have two irides in vicinity, we pulled out that one from the post.

Other things we noticed:

  • The POP beam is definitely clipping in the vacuum, looks like on two sides.
  • We can probably get better layout on the POP table, so we're not hitting mirrors at oblique angles and can get beams on grid paths.

After the alignment work on the tables, we started locking the cavity. We already saw the improvement of the POPDC power from 1000 cnt to 2500 cnt without any realignment.
Once PRM is tweaked a little (0.01ish for pitch and yaw), the maximum POPDC of 6000 was achieved. But still the POP camera shows non-gaussian shape of the beam and the Faraday camera shows bright
scattering of the beam. It seems that the scattering at the Faraday is not from the main beam but the halo leaking from the cavity (i.e. unlocking of the cavity made the scattering disappeared)


Tomorrow Jenne and I will go into BS to tweak the alignment of the TEMP PRC flat mirror, and into ITMX to see if we can clean up the POP path.

  8070   Tue Feb 12 20:42:36 2013 JamieUpdateAlignmentIFO alignment in prep for in-air PRMI

Yuta, Manasa, Jamie, Jenne, Steve, Rana

Starting this morning, we removed the temporary half PRC mirror in front of BS and started to align the IFO in prep for an in-air lock of the PRMI.

This morning, using the new awesome steerable active input TTs, Jenne and I centred the beam on PRM, PR2/3, BS, ITMY and ETMY.

After lunch, Yuta and Manasa aligned the Y ARM, by looking at the multi-pass beam.  The X-end door was still on, so they roughly aligned to the X ARM by centring on ITMX with BS.  They then got fringes at the BS, and tweaked the ITMs and PRM to get full fringes at BS.

We're currently stuck because the REFL beam appears to be clipped coming out of the faraday, even though the retro-reflected beam from PRM is cleanly going through the faraday output aperture.  The best guess at the moment is that the beam is leaving MC at an angle, so the retro-reflected beam is coming out of the faraday at an angle.  We did not center spots on MC mirrors before we started the alignment procedure today.  That was dumb.

We may be ok to do our PRMI characterization with the clipped REFL, though, then we can fix everything right before we close up.  We're going to need to go back to touch up alignment before we close up anyway (we need to get PR2 centered).

Yuta and Manasa are finishing up now by making sure the AS and REFL beams are cleanly existing onto the AS table.

Tomorrow we will set up the PRM oplev, and start to look at the in-air PRMI.  Hopefully we can be ready to close up by the end of the week.

ELOG V3.1.3-